电刺激顶盖前区前核对大鼠心包内注射辣椒素诱发的背斜方肌肌电的影响

Effects of Electrical Stimulation of the Anterior Nucleus of the Anterior Tectum on the Myoelectricity of the Dorsal Trapezius Muscle Induced by Intrapericardial Injection of Capsaicin in Rats

目的观察顶盖前区前核(AptN)是否参与心脏痛的调制。方法选择SD雄性大鼠18只,在戊巴比妥钠(50 mg/kg)腹腔麻醉下行心包插管术后,给予AptN分别施加强度10、25、50μA的电刺激(波宽3 ms,频率100 Hz),心包内注射辣椒素诱发心脏痛,记录对侧背斜方肌的肌电(EMG)。结果电刺激APtN剂量依赖式抑制大鼠心包腔内注射辣椒素诱发的背斜方肌的EMG(Y=87.939-1.585X,r=0.951,P=0.049),EMG反应相对于基础对照分别减小至(63.71±2.82)%、(37.65±5.75)%和(15.71±4.30)%(P<0.05),肌电反应较对照明显减弱,肌电幅值减小,放电频率减少,放电时间缩短,潜伏期延长。结论电刺激APtN,激活“APtN-中脑深部网状结构、脑桥臂旁核及网状旁巨细胞核-延髓外侧到脊髓”的多突触下行抑制通路,对心脏痛产生抑制性调节。

Objective To observe whether AptN is involved in the modulation of cardiac pain.Methods 18 SD male rats were selected.After pericardial intubation under intraperitoneal anesthesia with sodium pentobarbital(50 mg/kg),AptN was given to apply electrical stimulation of 10,25,and 50μA(wave width 3 ms,frequency 100 Hz),intrapericardial injection of capsaicin induced heart pain,and the electromyography(EMG)of the contralateral dorsi trapezius muscle was recorded.Results Electrical stimulation of APtN dose-dependently inhibited the EMG of rat dorsi trapezius induced by intrapericardial injection of capsaicin(Y=87.939-1.585X,r=0.951,P=0.049),and the EMG response was reduced to that of the basic control(63.71±2.82)%,(37.65±5.75)% and(15.71±4.30)%(P<0.05),the electromyographic response was significantly weaker than the control,the electromyographic amplitude decreased,the discharge frequency decreased,the discharge time shortened,and the latency period extend.Conclusion Electrical stimulation of APtN activates the multi-synaptic descending inhibitory pathways of"APtN-deep midbrain reticular structure,parapontine nucleus and parareticular giant cell nucleus-lateral medulla oblongata to spinal cord",which could inhibit cardiac pain.